I could focus you could focus she could focus we could focus you could focus they could focus
V-ing form
I could be focusing you could be focusing she could be focusing we could be focusing you could be focusing they could be focusing
Perfect
I could have focused you could have focused she could have focused we could have focused you could have focused they could have focused
V-ing perfect
I could have been focusing you could have been focusing she could have been focusing we could have been focusing you could have been focusing they could have been focusing
Negation
Simple form
I couldn't focus you couldn't focus she couldn't focus we couldn't focus you couldn't focus they couldn't focus
V-ing form
I couldn't be focusing you couldn't be focusing she couldn't be focusing we couldn't be focusing you couldn't be focusing they couldn't be focusing
Perfect
I couldn't have focused you couldn't have focused she couldn't have focused we couldn't have focused you couldn't have focused they couldn't have focused
V-ing perfect
I couldn't have been focusing you couldn't have been focusing she couldn't have been focusing we couldn't have been focusing you couldn't have been focusing they couldn't have been focusing
Interrogative form
Simple form
could I focus? could you focus? could she focus? could we focus? could you focus? could they focus?
V-ing form
could I be focusing? could you be focusing? could she be focusing? could we be focusing? could you be focusing? could they be focusing?
Perfect
could I have focused? could you have focused? could she have focused? could we have focused? could you have focused? could they have focused?
V-ing perfect
could I have been focusing? could you have been focusing? could she have been focusing? could we have been focusing? could you have been focusing? could they have been focusing?
Interro-negative form
Simple form
couldn't I focus? couldn't you focus? couldn't she focus? couldn't we focus? couldn't you focus? couldn't they focus?
V-ing form
couldn't I be focusing? couldn't you be focusing? couldn't she be focusing? couldn't we be focusing? couldn't you be focusing? couldn't they be focusing?
Perfect
couldn't I have focused? couldn't you have focused? couldn't she have focused? couldn't we have focused? couldn't you have focused? couldn't they have focused?
V-ing perfect
couldn't I have been focusing? couldn't you have been focusing? couldn't she have been focusing? couldn't we have been focusing? couldn't you have been focusing? couldn't they have been focusing?